1. Field of the Invention
The present invention relates to light detection, light switching and light modulation and more particularly to an optical transistor that realizes high speed optical modulation, optical switching and optical detection.
2. State of the Art
A great variety of devices utilizing various physical principles have been produced and used for light modulation, light switching and light detection. For example, physical effects used by existing infrared light modulation devices include Faraday magnetic deflection, optical analysis of variation, and the Kerr effect, all of which are realized by utilizing the variation of solid state optical properties under magnetic and electric fields. The manufacturing processes for such devices are all very complicated. For example, in Chinese Patent Application 92108312.2, entitled "New Measuring Method Of The Life of Nonequilibrium carrier" filed on Jan. 23, 1990 it was disclosed that the life time of carriers can be measured by using photo injection to move a reflection edge so as to make the incident light of another beam having a frequency on the reflection edge experience a drastic change in reflection from semiconductor surface. That principle can also be developed and applied in light modulation, light switching and light detection.